Microsoft 365 email disruptions continued into the night as Microsoft listed service degradation. Exchange Online-dependent features were affected; independent features remained functional. Outlook mailbox access through web, desktop, mobile and software interfaces might fail, and delivery could be delayed.
The University of Wisconsin-Milwaukee listed the incident as open and ongoing, starting at 10:17 a.m. Central on November 12. It warned email-dependent campus workflows could be affected.
Microsoft said Teams calendar, scheduling, invitations and meeting editing were affected, while core calls, meetings, group chats and channel messages were largely unaffected. Live or Virtual event creation and private or shared channel creation or deletion could fail; standard channels worked. Teams Copilot answers about Outlook, calendars or Microsoft 365 files could fail, as could reading chat history or adding to new chats. Navigating App chats and adding or syncing contacts could fail.
Copilot Chat might not load, respond or access work email, calendars or files. SharePoint Exchange-dependent features could fail, but directly stored files remained accessible. Some Microsoft 365 administration pages and recent file lists could fail; Microsoft 365 Apps admin center Cloud Update, Cloud Policy and Inventory, and Education Assignments, Reading Progress and Speaker Progress could be affected.
Microsoft reported possible failures exporting sensitivity-labelled Fabric reports to PDF or PowerPoint, updating labelled artifacts and opening labelled PBIX files in Power BI Desktop. Microsoft warned that all Power BI users could intermittently fail to export Microsoft Information Protection sensitivity-labelled reports to PDF. Microsoft mentioned label removal only where organizational data protection policies permit.
Microsoft Graph API requests for Exchange mail, calendar and contacts could time out, affecting Teams channel, member and app management and activity notifications. Intune enrollment, check-in and compliance policies could intermittently falter; Planner plan and task operations could be unreliable. Purview authorization, auto-labeling, label policies, Data Loss Prevention, Communication Compliance, Information Protection labels, role-based access control, classification, audit searches, protected content creation, eDiscovery searches and exports, and on-demand scanning could be affected; portal pages or protected content might not open. Windows 365 connectivity problems applied only where customers configured both their tenant and Cloud PCs with Purview Customer Key.
Microsoft reported possible Defender for Office 365 failures accessing Safe Links, Safe Attachments, protection and submission policies, Quarantine, Threat Explorer and viewing email remediation events. Microsoft said outbound protection and message traces could be delayed, alongside allow/block list changes, content extraction, reporting and role-based access control. Rewritten Safe Links URLs could fail to open; even users able to access Quarantine could fail to release items, and Defender XDR pages or solution tabs might not load. Microsoft To Do operations or loading and Universal Print submissions or administration could fail.
Earlier Microsoft updates carried by the university described an overwhelmed secure-connection process causing affected servers to stop processing requests, and a 9:34 p.m. Central assessment finding no indication of malicious activity. Microsoft now said it was adjusting traffic protocols, redistributing traffic and selectively blocking traffic. Partial regional recovery had not been sustained; further infrastructure stability measures were under consideration.